1. Field
The present invention relates generally to distributed file systems and protocols and, more specifically, to file security in peer to peer media sharing systems.
2. Description
There are at least several peer to peer media sharing systems in current use on computer networks such as the Internet. Napster™ is a popular system wherein a central server performs all searches for requested files and returns the names of files and their network addresses on each system in the network that match the request. In Gnutella™, another popular peer to peer system, users make search requests that are propagated throughout a network and perform searches on each machine in the network. In FreeNet™, there is no search ability. To retrieve a file using FreeNet, the user must already know the file's true name, which may be extremely difficult to guess.
Both Gnutella and Napster store index information to support searches outside the requester's machine (e.g., on other machines in the network), causing scarce network bandwidth to be consumed every time any user in the network performs a search for a desired file. Neither Gnutella nor Napster provide any hiding of files in the network. In either system, making a file available to one user of the network makes it available to all users of the network. This may be undesirable for personally-created files, because the owner may wish to make only certain files available to certain people, but not to the world at large. Napster or Gnutella could be modified to associate file access permissions with index information, but this produces other problems. In Gnutella, because index information is replicated as files are shared among network nodes, the system would then have to solve the problem of maintaining consistent permissions in replicated indices. In Napster, after adding permissions to each file in the main database, the system would still require a central server with the associated disadvantages of a lack of fault tolerance and difficulty in maintaining scalability.
For peer to peer file sharing systems supporting the sharing of personally created media such as digital photographs, videos, and music, the lack of privacy inherent in these systems is troubling to some users. Furthermore, the search capabilities of such systems are inefficient.